While audio is a valuable component of audio and video verification, it has limits imposed by the law. For one, it cannot be recorded unless everyone is aware that the audio is being recorded, Stadheim stated.
Bank ATMs, for example, have video but not recorded audio. Different states may have different requirements.
That does not reduce the effectiveness of audio. Many banks and prisons use audio monitoring with the highs and lows clipped out-the resulting audio gives the tenor of the conversation but the actual sound is not readily identifiable. Audio analysis allows the system to determine peaks and valleys in the sound. A sudden increase in sound intensity might alert the system to a problem.
Likewise, impact noises can be recorded. These are short, sudden sounds like a car crash or a gunshot. An impact spike in the audio, followed two minutes later by a 9-1-1 call would serve as validation of the call.
However, in situations like door stations, there is a reasonable assumption that someone is listening and is responding. There, audio is fair game for recording to a server.
Gonzales noted that there are legal aspects-legislation and ordinances-that cover all sorts of security from fire codes to access and egress. Video and audio are required to meet and comply with regulations or code in many jurisdictions. Like other vendors, Gonzales said their video is not recording all day. However, when an alarm is triggered the central station can look for a video clip to ascertain what is going on. "The system is designed to be activated when nobody is in the building," he explained.
The bottom line, Atteberry added, is to have a solid legal team behind you to be sure you and the client are protected.
Before you install
An IP-based camera and audio system are the easiest to use. Some cameras have audio integrated within. However, if quality audio is a key part of the system, i.e. for voice verification of identity, then an upgraded audio backbone will be required for more accurate sound.
According to Atteberry, IP has opened the doors to taking video beyond the rudimentary. "With IP, there is no need to retrofit for audio and video verification." He added that their platform integrates with most systems on the market. Simply link the DVR to the Internet and it's ready to go.
Audio can be trickier. For either video or audio, Stadheim said the first thing integrators should do is to meet with the network providers to make sure there are enough IP addresses and MAC addresses for an exclusive installation and enough bandwidth exists for all of the required subnets. "Engage early with the folks putting in the network and figure your total bandwidth needs," he explained.
While he says they have not been called upon to do a lot of audio and video verification systems, Marinace said the typical method is to integrate the verification with the video server at the site through a DVR at the central station. The operator can than log in and view a potential alarm scene.
"There is no need to retrofit the existing system," he said. Rather, an integrator can add the appropriate devices to the system.
Video and audio verification requires practical installation before it catches up to the high adoption rate of IP video, yet the continued development and maturity will pave the way for growth.
Curt Harler is a regular contributor to SD&I magazine and a freelance writer specializing in security and the construction industry. Reach him at firstname.lastname@example.org.